I am looking for an ornamental grass that doesn’t get over 5 feet tall
and am wondering what are the growing conditions for Miscanthus sinensis
(Gracillimus)? How much sun does it need, will it spread and invade my
other plants, is it invasive in our area (Seattle)?
I found several cultivars of Miscanthus listed on the local web site Great Plant
Picks. Miscanthus sinensis ‘Morning Light’ will reach about 5 feet tall
by 4 feet wide. This Colorado State University Extension article on from ornamental grasses may give
you additional ideas on grasses for your garden.
Although the following link is for southwest Washington gardens, this
Washington State University list of ornamental grasses may be of use.
It includes Miscanthus sinensis ‘Gracillimus,’ and indicates it does not
have a problem with self-seeding.
Excerpt:
Miscanthus
BE CAREFUL! Many are self-seeding.
M. sinensis ‘Gracillimus’ Maiden grass 4.5′ FS Most popular. Seldom
self-seeds.M. sinensis var. purpurascens Purple maiden grass, Flame grass 3 – 5′ FS
Gorgeous red-orange fall foliage. One of the earliest flowering varieties
of maiden grass.M. sinensis ‘Silberpfeil’ Eulalia 4 – 5′ FS One of the hardiest varieties
of maiden grass.M. s. ‘Morning Light’ Dwarf maiden grass 4 – 5′ S, LSh Arguably best
all-around plant of the Miscanthus group. Blooms late with reddish
flowers.M. s. ‘Adagio’ Japanese silver grass to 3.5′ S, LSh Compact with
silver-gray foliage. Two- to three-feet long panicles emerge pink, fade
to white.M. s. ‘Flamingo’ Japanese silver grass to 6′ Large, loosely open,
pink-tinted inflorescences. Slightly pendant blooms appear late summer.M. s. ‘Sarabande’ to 6′ Similar to Gracillimus, but finer textured.
Golden copper colored inflorescences in August.M. s. ‘Strictus’ Porcupine grass 4 – 6′ FS One of the hardier Miscanthus
cultivars. Tolerates wet soils.M. s. ‘Variegatus’ Variegated silver grass 4 – 6′ S, PSh Prefers
moist, fertile, well-drained soil.M. s. ‘Zebrinus’ Zebra grass 4 – 8′ S, PSh
Update from 2012 on the invasive potential of Miscanthus cultivars:
Wendy DesCamp of the Washington State Noxious Weed Control Board reports the following:
“There is now a record of the plant growing in eastern Washington by the Columbia River in Benton County. [described as follows:] Shallow backwater on N shore of Columbia River . . . below McNary Dam, elev. 85 m, 45 degrees, 55.9 minutes N, 119 degrees 21.4 minutes west. Collected by Peter Zika, 17 June 2011.
From what I can find, this is the first collection of naturalized Miscanthus sinensis collected in Washington.”
The State Noxious Weed Board is considering whether it should be added to the monitor list or not. The monitor list is a list of plants the Board is keeping track of to collect information and to see if the plants are occurring or spreading in Washington.
UW Botanic Gardens Director, Professor Sarah Reichard had this to say about Miscanthus sinensis:
“We have had it in the Soest Garden for years and I have not seen it invade and I am looking for seedlings. However, not invading in the artificial environment of a garden, with water and nutrient inputs means little for invasion in the wild. I have not heard of it being invasive here, and I have been paying attention to both this species and Imperata cylindrica.It might be a good addition to the [noxious weed] monitor list.”